[103.01] The Importance of Comet Hale-Bopp: An Astronomical Perspective

L.A. McFadden (U. Maryland)

Comet Hale-Bopp is repeatedly recounted in numerous
scientific papers as the comet of the century. Extensive
research has provided new insights into the cold and distant
residual material of the solar nebula. Both technology and
astute colleagues have created comparisons with other comets
and with the chemistry of dust and gas in the interstellar
medium. We have new insights into the dynamics and
conditions of cometary processes and to conditions and
chemistry that may have been set prior to incorporation of
this matter into the solar nebula. A clearer picture of
comets also allows us to understand the bodies that have
shaped the surfaces of the planets over the past 4.6 b.y.
Hale-Bopp was 11th magnitude at its discovery at r(h)=7.15
AU on July 23, 1995. It was a bright and distant comet
compared to most recently discovered ones at 17-18th
magnitude seen first inside of 4 AU. Hale-Bopp's brightness
and early discovery permitted a long observation window that
culminated at perihelion at 0.91 AU on 1 April, 1997 and
continues today with the comet > 10 AU with a modelled total
magnitude ~12.6. Its orbital elements establish that it is a
long period comet that has passed through the solar system
previously. Using several indirect image analysis techniques
a diameter between 35-40 km is derived. Hale-Bopp is big by
any standard of comet nucleus (Halley's triaxial diameters
are 16x8x8 km). It was also active in terms of both dust and
gas production, with numerous outbursts having been observed
on both its inbound and outbound passage through the inner
solar system. More than 50 observed molecules, radicals and
ions have been observed some of which can be distinguished
as presolar in origin. This work has been supported by
NASA's NEAR and Deep Impact missions and U.Md.

If you would like more information about this abstract, please
follow the link to http://www.astro.umd.edu/~mcfadden/halebopp.
This link was provided by the
author. When you follow it, you will leave the Web site for this
meeting; to return, you should use the Back comand on your
browser.

The author(s) of this abstract have provided an email address
for comments about the abstract:
mcfadden@astro.umd.edu